Dump options in backupable DB

Summary: We should dump options in backupable DB log, just like with to with RocksDB. This will aid debugging.

Test Plan: checked the log

Reviewers: ljin

Reviewed By: ljin

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16719

include/utilities/backupable_db.h

@@ -55,6 +55,8 @@ struct BackupableDBOptions {
   // Default: false
   bool destroy_old_data;
 
+  void Dump(Logger* logger) const;
+
   explicit BackupableDBOptions(const std::string& _backup_dir,
                                Env* _backup_env = nullptr,
                                bool _share_table_files = true,

utilities/backupable/backupable_db.cc

@@ -26,6 +26,15 @@
 
 namespace rocksdb {
 
+void BackupableDBOptions::Dump(Logger* logger) const {
+  Log(logger, "       Options.backup_dir: %s", backup_dir.c_str());
+  Log(logger, "       Options.backup_env: %p", backup_env);
+  Log(logger, "Options.share_table_files: %d", share_table_files);
+  Log(logger, "         Options.info_log: %p", info_log);
+  Log(logger, "             Options.sync: %d", sync);
+  Log(logger, " Options.destroy_old_data: %d", destroy_old_data);
+}
+
 // -------- BackupEngineImpl class ---------
 class BackupEngineImpl : public BackupEngine {
  public:
@@ -205,6 +214,8 @@ BackupEngineImpl::BackupEngineImpl(Env* db_env,
       backup_env_(options.backup_env != nullptr ? options.backup_env
                                                 : db_env_) {
 
+  options_.Dump(options_.info_log);
+
   // create all the dirs we need
   backup_env_->CreateDirIfMissing(GetAbsolutePath());
   backup_env_->NewDirectory(GetAbsolutePath(), &backup_directory_);